CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Operating Revenues	$ 2,290,590	$ 1,995,023
Operating Expenses:
Purchased Power and Transmission	978,150	747,809
Operations and Maintenance	351,688	346,092
Depreciation	150,807	154,977
Amortization of Regulatory Assets/(Liabilities), Net	57,898	54,049
Amortization of Rate Reduction Bonds	0	34,499
Energy Efficiency Programs	138,825	105,771
Taxes Other Than Income Taxes	145,533	132,881
Total Operating Expenses	1,822,901	1,576,078
Operating Income	467,689	418,945
Interest Expense:
Interest on Long-Term Debt	87,377	85,906
Other Interest	2,598	(9,651)
Total Interest Expense	89,975	76,255
Other Income/(Loss), Net	1,667	7,765
Income Before Income Tax Expense	379,381	350,455
Income Tax Expense	141,545	120,487
Net Income	237,836	229,968
Net Income Attributable to Noncontrolling Interests	1,879	1,879
Net Income Attributable to Controlling Interests	235,957	228,089
Diluted Earnings Per Common Share	$ 0.74	$ 0.72
Basic Earnings Per Common Share	$ 0.75	$ 0.72
Common Stock Dividends Per Share Declared	$ 0.39	$ 0.37
Weighted Average Common Shares Outstanding:
Basic	315,534,512	315,129,782
Diluted	316,892,119	316,002,538
The Connecticut Light And Power Company [Member]
Operating Revenues	734,614	624,097
Operating Expenses:
Purchased Power and Transmission	281,381	229,259
Operations and Maintenance	109,514	108,895
Depreciation	46,130	42,448
Amortization of Regulatory Assets/(Liabilities), Net	29,931	10,787
Energy Efficiency Programs	42,694	22,813
Taxes Other Than Income Taxes	66,953	60,192
Total Operating Expenses	576,603	474,394
Operating Income	158,011	149,703
Interest Expense:
Interest on Long-Term Debt	32,908	32,635
Other Interest	1,335	(2,941)
Total Interest Expense	34,243	29,694
Other Income/(Loss), Net	1,072	4,187
Income Before Income Tax Expense	124,840	124,196
Income Tax Expense	45,541	39,188
Net Income	79,299	85,008
NSTAR Electric Company [Member]
Operating Revenues	666,188	592,257
Operating Expenses:
Purchased Power and Transmission	319,082	214,053
Operations and Maintenance	85,924	92,301
Depreciation	46,626	45,441
Amortization of Regulatory Assets/(Liabilities), Net	15,664	46,994
Amortization of Rate Reduction Bonds	0	15,054
Energy Efficiency Programs	48,329	51,703
Taxes Other Than Income Taxes	32,151	32,174
Total Operating Expenses	547,776	497,720
Operating Income	118,412	94,537
Interest Expense:
Interest on Long-Term Debt	20,756	19,991
Other Interest	304	(4,068)
Total Interest Expense	21,060	15,923
Other Income/(Loss), Net	(31)	773
Income Before Income Tax Expense	97,321	79,387
Income Tax Expense	39,234	31,265
Net Income	58,087	48,122
Public Service Company Of New Hampshire [Member]
Operating Revenues	299,833	273,829
Operating Expenses:
Purchased Power and Transmission	115,246	101,024
Operations and Maintenance	62,212	59,729
Depreciation	24,215	22,568
Amortization of Regulatory Assets/(Liabilities), Net	12,562	(3,051)
Amortization of Rate Reduction Bonds	0	14,756
Energy Efficiency Programs	3,839	3,669
Taxes Other Than Income Taxes	17,715	17,016
Total Operating Expenses	235,789	215,711
Operating Income	64,044	58,118
Interest Expense:
Interest on Long-Term Debt	11,526	11,881
Other Interest	445	287
Total Interest Expense	11,971	12,168
Other Income/(Loss), Net	265	1,030
Income Before Income Tax Expense	52,338	46,980
Income Tax Expense	19,700	17,984
Net Income	32,638	28,996
Western Massachusetts Electric Company [Member]
Operating Revenues	137,409	124,953
Operating Expenses:
Purchased Power and Transmission	49,431	40,044
Operations and Maintenance	22,579	20,928
Depreciation	10,321	8,970
Amortization of Regulatory Assets/(Liabilities), Net	399	129
Amortization of Rate Reduction Bonds	0	4,689
Energy Efficiency Programs	11,865	8,315
Taxes Other Than Income Taxes	8,082	6,288
Total Operating Expenses	102,677	89,363
Operating Income	34,732	35,590
Interest Expense:
Interest on Long-Term Debt	6,062	6,082
Other Interest	(416)	211
Total Interest Expense	5,646	6,293
Other Income/(Loss), Net	574	1,004
Income Before Income Tax Expense	29,660	30,301
Income Tax Expense	11,558	11,698
Net Income	$ 18,102	$ 18,603